BCD process is a monolithic integrated processing technique, which can fabricate Bipolar, CMOS and DMOS devices on the same chip, and is simply referred to as BCD process. Since the BCD process incorporates the respective advantages of the three devices above, it becomes a leading processing technique in the integrated circuits. The BCD processing technique has been developed for many years and has many proven processing solutions. The BCD process may select different devices for different circuits to optimize the respective electric circuit devices, achieving the requirements of low power-consumption, high integration, high speed, and high driving capacity of the whole circuit. The BCD process is an excellent choice for IC manufacture process such as power management, display driving, auto electronics, etc., and has a wide market prospect.
As the enhancement of the national energy saving and consumption reducing, the high-power semiconductor discrete device industry develops continuously, quickly and steadily, and the industry scale is increasing. The electrical and electronic power modules and components with a high-voltage integrated circuit as a core high-voltage power switch device are applied more and more widely, and are progressing in three different research directions of high voltage, high power, and high density. For example, the high-voltage integrated circuit in the inverter motor driving circuit for the three-phase AC 380V, 440V, and 480V power supply employs a 1200V high-voltage BCD process product. For the 1200V high-voltage BCD process, besides the development of the essential 1200V high-voltage LDMOS devices, it is also necessary to develop an isolation structure to effectively isolate the epitaxial island where the high-voltage device is located. Meanwhile, a parasitical effect caused to the silicon surface by the high voltage on the aluminum wiring of the high-voltage device must be considered, e.g., the parasitical threshold voltage between aluminum wiring and the silicon surface of the 1200V device must be higher than 1200V.